Even on a first name basis, no one would mistake Steve Ballmer for Steve Jobs.

One led a revolution in music, mobile, and form factor. The other saw the decline of a once-mighty empire while at the helm.

And influential hedge fund manager David Einhorn has taken notice.

At an investor conference in New York, the Greenlight Capital head publicly asked for Steve Ballmer step down from his CEO post at Microsoft. Despite being long on Redmond, he has no faith in the out-of-touch CEO to lead the company toward greener pastures, citing Ballmer's missteps in the tablet industry and wasting money on lackluster investments and acquisitions. Even the Ballmer's refusal for his family to use Apple or Google products shows a delusional personality separated from the rest of the world.

Einhorn said it was time for Ballmer to step aside and "give someone else a chance." He added, "His continued presence is the biggest overhang on Microsoft's stock."

And Einhorn isn't wrong. Microsoft's stock has plummeted since Ballmer took the reins from Bill Gates in 2000, falling 50%. The company's online service division is also failing, having lost $7 billion in the last four years.

Einhorn has company in his dissatisfaction. According to an SEC filing last September, Microsoft's board of directors have had it with Ballmer's poor performance. The filing noted "the unsuccessful launch of the Kin phone; loss of market share in the company’s mobile phone business; and the need for the Company to pursue innovations to take advantage of new form factors." In fact, because of Microsoft's flagging mobile development, Ballmer had his bonus halved.

As far as the smartphone industry is concerned, Windows Phones have a long way to go to catch up with Android, iPhone, and BlackBerry. Somewhat fitting it aligned itself with fellow has-been Nokia, isn't it?

The turnover rate within the company has also been very disconcerting. Key executives like Chief Software Architect Roy Ozzie, Xbox and Zune leader J Allard, Entertainment & Devices Division head Robbie Bach, and Business Division head Stephen Elop are no longer with Microsoft. Add the thousands of employees who've been laid off or fired, and Microsoft doesn't seem to be headed in the right direction.

Clearly, as Einhorn said, things aren't working with Ballmer in charge.